1. Field
The presently disclosed subject matter relates generally to fluid flow devices, systems, and related methods, and more specifically to a valve device, fluid delivery system and method for operating the valve device to infuse fluids to a patient.
2. Description of the Related Art
A directional control valve can be used to control the direction of fluid flow from one component of a fluid system to another component of the fluid system. The directional control valve can allow fluid to pass through the directional control valve in a first direction and can prevent, or substantially prevent, the flow of fluid through the valve in a second direction that is typically a direction opposite to the first direction. The directional control valve can also limit fluid flow through the valve in the first direction.
A ball check valve is an exemplary directional control valve that includes a ball biased against a mating valve seat by a spring. The spring biases the ball against the seat to seal the valve against fluid flow in the second direction. If the fluid pressure on the upstream side of the ball is greater than the bias force applied by the spring, the fluid pressure will unseat the ball from the valve seat permitting fluid to flow through the ball check valve. The ball check valve is an example from the family of back check valves that are typically referred to as normally closed check valves because the valve member is normally biased into engagement with the seat (i.e., closed) when no fluid pressure (in either direction) is exerted against the valve member.
There may be a desire to override or bypass the normally closed check valve to permit the fluid to pass through the valve in the first direction, regardless of pressure. On other occasions, it may be desired to override or bypass the check valve to permit fluid to pass through the check valve in the second direction. Typically, the check valve is removed from the fluid system in order to accomplish either of the immediately above-described desired flows through the check valve. However, this operation can require a shut down of the fluid system until the check valve is removed and replaced with another component, such as a conduit. Once the desired bypass flow is complete, the fluid system is disassembled and the check valve is re-inserted therein.
Medical fluid delivery systems can include a normally closed back check valve in order to prevent aspiration of infusate, blood or other fluid away from the patient. Certain desired treatments for a patient can include a step in which a fluid is aspirated either away or from the patient using the fluid delivery system. In order to accomplish this step, the normally closed check valve can be removed from the fluid delivery system prior to the aspiration and then re-inserted into the fluid delivery system subsequent to the aspiration. The removal and re-insertion of the normally closed check valve can complicate the aspiration treatment through the removal and re-insertion steps.
Recently, there have been efforts to provide a bypass device that can open the normally closed back check valve without removing the check valve from the fluid delivery system. Such a bypass device can increase the versatility of the fluid system while maximizing the efficiency and sterility of the fluid system during the transition to and from the bypassed state. In addition, such a fluid system can reduce the time necessary to undertake certain procedures that call for reversal of flow through a check valve.